I have a boom mike, I'm going xlr mono because it one mic, is there any settings to make that mono in two channels,L/R, or do I have to buy the splitter from one xlr in to two?

Another problem was When I filmmed shinny cars driving slowly in the street and the light moves on the shinny parts the video look jagged in thos spots, shot 30p 60i? the car moving 5 mph

I think you need a splitter, but I'd have to check my manual. You might want to consider a small portable mixer (I use a Samson Mixpad 4, runs on batteries, can carry it on my shoulder if needed) that way it will split to two channels so I can record one channel normal db, another -10db so I can use it if clipping occurs on the main track.

Per jaggies in highlights. If you are using the cine-gamma setting, it provides no headroom in highlights. Overexposing any part of the frame will result in artifacts. You might was to consider a polarizer filter or set you zebra's lower to avoid hot spots. A diffusion filter can some times work, but that softens the whole image.

This one's easy. Just assign both audio channels to channel two. Then connect your XLR to channel two. The controls are behind the LCD.